Could someone explain which type of rubber has the most grippiness?

[NathanRidge]

I'm in the process of modifying my wheelchair. Currently, I'm deliberating on covering the aluminum handrim in a rubber of some sort, much like the nubby rubber on steering wheel covers.

Because it doesn't look like I'll be able to find a steering wheel cover made entirely of the nubby rubber, I started looking at rubber sheets.

Predominantly, I'm looking for a rubber with high grippiness--i.e. it's easy to grab with a gloved or non-gloved hand, and makes it easier to propel the chair forward.

That being said, I also need the rubber to be sturdy enough to withstand the strain it will be put through yet weatherproof enough not to deteriorate in any weather condition. I know some rubbers tear easily in the cold, so I'd like to have the rubber's lowest temperature be below 0 degrees fahrenheit, since that's the coldest it's ever been where I live. Lastly, I'd like for the rubber to have some bounce or give to it, so that when the wheel inevitably brushes against a curb or brick or other hard object that it doesn't tear and hopefully protects the handrim.

Could someone explain to me exactly what I should look for to meet as many of these qualifications as possible? I'd like to know what type of rubber and any specific terms I should keep in mind when I'm shopping for the rubber sheets.

I was thinking maybe silicone rubber, but then it occurred to me there is more than one type of silicone rubber, like there is more than one type of regular rubber.

Thanks for the help.

 

[PratsA]

While I'd love to delve into issues of durometer and yield strength, the practical part of me is just going to suggest you look at a product called Plasti Dip. It's a great way to coat metals for grippiness and protection.

If you decide to go that way, make sure you use the primer. Otherwise I'd be concerned about bonding to the highly polished handrim.

If this is too simple a solution, I'm sure we can come up with some more fun options....

Antonio

 

[NathanRidge]

@ PratsA

Thank you for the reply, and I apologize for my delay in responding; most of my time had been taken up designing and redesigning a cup holder for my wheelchair.

I looked up Plasti Dip and it intrigues me, although I have to wonder if I could easily coat both wheel rims in an even layer? I saw it comes in multiple application methods, including a spray can and a brush on method. Which method would you suggest, and what tips can you give on how to get an even coating?

Also, I think my hand rims might be powder coated. They're not polished like the wheelchairs you find in hospitals; they're covered in some kind of black coating. I don't think it's paint, because I can't find anything else that feels the same but it might just not be a commercially available paint.

Because I was uncertain I could apply a liquid or spray-on rubber properly, I was leaning towards enclosing the hand rim in a rubber sheet. I had two ideas about how I could attach the rubber. The first was to wrap strips of rubber around the handrim, sort of like wrapping bandages. The second idea would fold a single, long strip of rubber about two inches wide over the hand rim. In either case, I expected to screw the rubber into the hand rim, and possibly sew or wrap the rubberized hand rim in some sort of durable string.

Does either idea seem like it would work?

 

[GregLocock]

"The first was to wrap strips of rubber around the handrim, sort of like wrapping bandages"

Racing bike handlebars used to use a spiral bandage of leather or plastic. They were basically useless for transferring any serious amount of force, repeatedly.

"The second idea would fold a single, long strip of rubber about two inches wide over the hand rim."

yup, that would work but the seam may annoy you.

What do the guys who race wheelchairs use?




Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[GrahamBennett]

"What do the guys who race wheelchairs use?"

According to my sources, wheelchair racers use sailing gloves - mesh back with either a leather or chamois leather palm and fingers.

 

[GregLocock]

There's a lot to be said for leather - it is stronger than rubber in tension.

Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[NathanRidge]

"They were basically useless for transferring any serious amount of force, repeatedly."

That's what I thought but my dad insisted it would work; I thought wrapping it like a bandage might need to be rewrapped every few weeks. Or, that the overlap of the strips would lead to the rubber wearing out faster.

"According to my sources, wheelchair racers use sailing gloves - mesh back with either a leather or chamois leather palm and fingers."

I'll have to try out some sailing gloves; normally I use bike gloves. I've tried several different companies and designs, although the one that works best has what I believe is synthetic leather on the palm. That works really well and grips the hand rim relatively well. The only problem is that these gloves only come in fingerless varieties, and I need full-fingered gloves for the winter.

"There's a lot to be said for leather - it is stronger than rubber in tension."

I agree and most of the decent wheelchair gloves I have used have a leather or leather-like palm. The reason I was leaning towards rubber was because I was under the impression leather deteriorates rapidly when wet. The amount of mud and rain the hand rims get exposed to led me to believe leather wouldn't work in the long run.

Also, my favorite pair of full-fingered gloves had silicone rubber on the fingertips; the grip the silicone fingertips gave me surpassed everything I'd used prior to that.

I have a new pair of wheelchair gloves coming in the mail from the same company that made my favorite full-fingered pair. These are the more expensive pair produced by the company, and after I get a feel for how they work, I'm going to talk to the company about custom making a pair to suit my needs.

However, I wondered if covering the hand rims was feasible because the metal occasionally gets scratched and scraped, leaving sharp burrs sticking up. I thought by covering the hand rims and protecting them from future scrapes I might be able to improve the lifespan of my wheelchair gloves and hopefully my ability to control the wheelchair.

 

[GregLocock]

Sailing gloves definitely come in full finger guise. They will cope well with water obviously but may not be waterproof as such. Grip may not be as good as silicone.

You could use a 2 pack polyurethane painted or moulded onto the rim. Sorry, haven't got any idea for brand names. You'd probably want something with a hardness of less than 50 SHure.

Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[GrahamBennett]

What about trying a pair of Neoprene diving gloves?

 

[SealGuru]

Try using SBR.
Or better yet use this chart to pick out what you think is more important.

http://mykin.com/index.php/material-properties

Michael

http://www.mykin.com